Fig. 1

Scheme of possible outcomes following chemotherapy treatment. There are three possible outcomes from chemotherapy treatment. a Intrinsic resistance to chemotherapy associated with the tumor cell quiescent state is usually defined by over-expression of ABC drug transporters, different anti-apoptotic genes and a more effective DNA repair system. b Acquired resistance that occurs despite initial positive response to therapy; here, different signaling pathways between secretome-educated cancer cells and MSCs are involved and c) Acquired chemo-resistance mediated by secretome-educated stromal cells through altered secretion profiles and different signaling pathways